Stern tube safety ring assembly



July 5, 1960 w, VALD] EIAL 2,943,874

STERN TUBE SAFETY RING ASSEMBLY Filed Sept. 19, 1955 2 Sheets-Sheet 1 Aas 6 I INVENTORS 68 64 2G WALTER J I/A E MME TT 7./(/

f/GLZ 42 32 1s WW4 /446 ATTORNEYS July 5, 1960 W. J. VALD] STERN TUBESAFETY RING ASSEMBLY Filed Sept. 19, 1955 2 Sheets-Sheet 2 INVENTORSWALTER J WILD! EMMETT 7. KING r r s 2,943,874

. Patented July 5, 1960 operation, e.g. the assembly has but one movingpart and requires only one gauge and one valve for. operation; and

' to provide a stern assembly which cannot damage the 2,943,874propeller shaft, stern tube, or bearing of a ship; and to STERN TUBESAFETY RING ASSEIVIBLY Walter J. Valdi, 2546 43m m, and Emmett 'r. King,846 Clayton St., both of San Francisco, Calif.

Filed Sept. 19, 1955, Ser. No. 534,986 2 Claims. 01,. 286--26) Thisinvention relates 'to propeller-driven seagoing vessels, and moreparticularly to a stern tube safety ring assembly adapted to be disposedwithin the stuffing box for the propeller shaft and to be pneumaticallyoperated, when the propeller shaft is not in motion and while the shipis afloat, to seal the" stuffing box against the influx of sea water andenable worn and leaking packing rings to be replaced.

Practically every ships engineering officer has been faced at one timeor another with theproblemof dealing with excessive leakage of sea waterthrough the ships stern tube gland. Minor leakage which can be handledby the ships pumps presents merely .an inconvenience problem. Butleakage to a degree beyond the capacity of the pumps results in theflooding of shaft tunnels or machinery spaces and other casualtiesunless .steps are promptly taken to stop the influx of water. At thepresent time, there is only one way of replacing worn and leakingpacking rings with complete safety, and this is .by dry docking the shipand then making the packing ring change. However, it quite frequentlyhappens that time, distance and operational requirement factors makeimmediate dry docking impossible. Moreover, dry docking amounts to aconsiderable item in operational expense.

When certain types of vessels are in still water, it is possible toshift weights forward, thus causing the vessel's propeller to be liftedout of the Water'to prevent-leakage through the stern gland whilepacking is being replaced, but this is done at great risk to thestability of the vessel and also at the further risk of subjecting thevessel to damaging stresses and strains. Furthermore, the occasions whenall weather and sea conditions are appopriate for the use of this methodof packing replacement are so infrequent as to prevent this method frombeing employed in the course of usual operations.

A further method which has beenemployed to stop the influx of sea waterand enable packing replacement while the vessel is at sea involves thesending of a diver over the stern to wrap a rubber boot, or mattress,about the propeller shaft where it enters the hull. The use of thismethod not only requires diver personnel and sea conditions appropriatefor underwater Work by the diver, but the shape of the shaft and thebearing housingmust be such as to enable the rubber boot tosatisfactorily accomplish its sealing function.

The stem tube safety ring assembly of the present invention fully solvesall of the problems involved in replacing stern tube packing while aship is afloat, and enables the same degree of safety to be attained asis attained by way of a dry docking operation.

Among the objects and advantages of the invention are the following: toprovide a safety ring assembly which is readilyinstallable in the sterntube of any ship andwithout requiring stern tube alterations forinstallation; to provide a safetyn'ng assembly which is compact to thepoint of occupying the space'of only a single ring of packing; toprovide a stern tube assembly which is substantially foolproof,andsimple in structure and mode of provide a safety ring assembly whichmay be used in bulkhead flange stuffing boxes through which thepropeller shaft passes to prevent leakage from adjacent floodedcompartments.

Other objects and advantages of the invention will be apparent from thefollowing description taken; in conjunction with the drawings formi gpart of this specification broken away to show the safety ring assemblyof the invention in place therein;

Figure 2 is an enlarged detail view'of the sectional showing of thesafety ring assembly of Figure 1;

Figure 3 is a sectional view of the safety ring assembly,

taken at a point other than the air line connection region shown inFigures 1 and 2 and showing the inflatablesafety ring in anon-inflatedcondition;

Figure 4 is a view similar to that of Figure 3, but showing the ringelement in an inflated condition;

Figure 5 is a view in side elevation of the safety ring housing portionof the assembly;

Figure 6 is an enlarged detail view in section taken along lines 6-6 ofFigure 5;

Figure 7 is an enlarged detail view in section taken along lines 7-7 ofFigure 5; V

Figure 8 is a view in section showing a modified form of the safety ringassembly; and

Figure 9 isa view in perspective of a single length split typeinflatable safety ring. p I

With initial reference to Figure 1, thestern tube assembly of a shipcomprises a stufiing box tube 10 having a rearwardly disposed annularfiange v12 secured to hull '14 in surrounding and sealing relation to ahull opening for propeller shaft .16 and having a forwardly disposed.

flange 18 and an inwardly disposed annular shoulder 20, a follower ring22 having an annular flange 24, a plurality of packing rings 26 disposedwithin'the stufling box tube 10 in surrounding relation to shaft 16 andadapted to be conventionally pressed against shoulder 20 to eflfect awater seal along the propeller shaft, and a plurality of bolts 28extending through flanges 18 and 24 and adapted to maintain theend ofthe follower ring 22 in pressing relation with the packing rings 26 bynuts 30. In the course of normal operation of the ship, the packingrings 26 become worn due to the wear imparted thereto by rotation ofshaft 16, and thus it becomes necessary,

to continually adjust the follower ring 22 inwardly of stufling box tube10 to maintain a sealing pressure of the packing rings against the shaftand stufling box tube.

When the follower ring has been adjusted inwardly of the stuffing boxtube to the maximum amount possible,

the packing rings are thereafter no longer pressable. Fur-' ther wear.of the packing rings leads to the influx of sea Water along shaft 16,thus requiring that new or additional packing rings he added in orderthat-a sealing pressure may be maintained. However, any backing oif ofthe follower ring leads to increased leakage, and thus it is notfeasible for new or additional packing rings 'to be installed when thestern tube is located below the surface of the water. 7 v The safetyring assembly of the invention makes it possible, as above stated, fornew or additional packing rings to be installed, once the rotation ofshaft 16 has been stopped, while the ship is at sea or afloat.

The safety ring assembly 32 of the invention, which is adapted to bedisposed between the shoulder 20 of stuff ing box tube 10 and theendmost packing 26, comprises vu edih eto,

earan epreven Wee area are brought m 'rjt e a i e qrq lll aden a afpairof annular ring members 34 and 36 which, when they are disposed inmating relation, as'shown in' 'Fignres 3, 4 and 7, define therebetweenan annular recess msa a vv e era l at 38,.. ais'1 re essha in a rt esepta "w. tes iy and, s9, n a nfl b -r b er ube 2; a 1 'he n Tis e PQ."44" ada ted t j i i a d; n taia a P sdfin 4, w ic s t rm d' i w h' Q e.aro 3 h tub "4.2; a y be ng: i s ndicat d n F ures- 5 andg ,4 is Qmletf wo s Qul rIpa tsA nd 10 formed of'two 'se i-circularparts 52' een' th48 e ees in "the nn pl t arm ,d 'dvei' i 9 E? res rmed infstufli g ber 'ensblfi la he stats nee, while the inside ch thatlit l arsjthe,

' 02 tnba iii l I diameter of'thi'ring assembly w h ft 6 th he same r iht y eats? q ee an theiiis'idediametenof he stuflingbox tube shgnldf gqlieihatt a s xlaala e stra I v brating V yn a a h pe rosszb n l adapteatmgjrelati and enveloping, relai ,tion with fespe 't, y

V l 54nd islll nte slbst ntial degr eof finanqihemetat ring;

11 1",- Io atiue movement;

pfrthemropeller shaft andt ewat round the haft.

I lmflrt t beA2,toamoyeintromrits.,d I ,sqkp. nsof; Fig r -.1andjrwherein; it 1s d spgse d;fully 1n rdly vof;;: he.trnetal, ringzassem- 55 3 3 l il li ifi lldfinjh sfullywinwardposition U r, v ann erl;hereto by... T-shapecLfin g i fivili flfiu d a gp e 4, whereinzthettubent sassa a astthe b it. 16r.and.prevents the.

Qffi L-W g, l llg the;;shait;.whi l e paclgingr 0 mo ed fin fliplafiegle omprises'; 1 a plug 162 formedjn; the inetal 'ring r ssqn lece l tobQth a pr ssur a fl through a control valy e;;78 amvair1line;;8.0;: and a -n11 t. 82:lin nt with stemflO; and adapted-to pressg was her against the stuifinglbox shell, topree a sage o wat r, hrougetheshe ei zthe stu fin safety ring assembly and the" propeller: shaft.

Insp ct to ga k t 8 6 1 T e ends, the closed endsbeing other he hetubenfl teias villustrat a a e A modified form of the safety ring' assemblyisshofwn inr g fl, w erein-parts identicaltwith those previouslydescribed are; designated by; the same ref rence, numeralsf 1 andwherein parts corresponding'tdthe m ple/1011 V described .are/identified by corresponding numerals plus}; 100. I In thisparticularmodification; the 'ing' memljer box s hellin which thestem 70 isdisposed." 'lhe, line is connected to a source of pressurized air, notshown, such as the ships air system, or even a hand pump. The gauge 76measures the air pressure within tube 42 when the tube is inflated, andprovides, once the tube has been I inflated and valve 78 has beenclosed, an indication as to whether the properisealing pressure is beingmain tained within the tube during use. 7

Ana'nnular gasket 8:6 is'provided between the safety ring assembly andthersboulderlfl of thelstufiing box. shell to prevent. any leakage ofwater therebetwe'en when the tube 42 is inflated'to seal off the spacebetween the With respect to thetube42, the'short tubular extension. 66thereof constitutes the only interruption of the continuity v of theT-shaped fin 46.1,.111 order to adapt the tube 42 to be placed over a.propeller shaftwhich is alreachg in place, the tube is initial] formedone length thefform of a single length 136, overlies the :ring niemb'er13.4" which ;is;seeur ed thereto. bybol'ts 156, the arrangement beinglrh l f 7 side oftube] 42, is in engagement with'the stuffing bozo shellshoulder} 20. both when, tlieiube. is inflated audition;

inflated. The tube 42,1when inflated, serves. torseal ofi Vthespacebetween the. safety ring QSS'embly andlsliaft -16" and.v to alsofseal off-the. spacexbetween the safety; ring i assembly and thevstufling box shell. 10. As' aprecautionary'measure, a sealing .gasket18 2 fitted within a' groove formed in the periphery of. ringmember 1316may; be employed to, insure that no leakage will occur, between thesafety assembly and the stufling'boxshelllwhen the tube, 42 has beeninflated and thelworn-packingnis,

being replaced,

From the foregoing description, it will be clearly seenthatthe'simplicity of the safetyring assembly, t'rom;tl: e standpoint ofconstruction, installation, andntodeofbp y, eration, render'ittroublerfree-vin maintenance and opreration. While specific, embodimentsof the invention have been shown and described, ,it-is to be understood.that all substantial equiyalents thereof are considered to be within thespirit andv scope-of the invention,

While the stern tube-embodiment,of,the invention for use-i hin s pe apst e [most mrtan i l se? QE h I fiQI ih epms n ly t mpl es ti li. bevappreciated that the inve nti,o,n; isw not limited to such. applicationand may: bereadily employed in: such shore nste la i n as o l lls nustrialv plants; and; 891mm,; Le wherever there maybe a; need to;temporarily seal.

off; one area of shaft;surro,

rs n z.- pace fromianother; h s; laim d i r a 1. A safety ring assemblyadaptedito; be Q the stufling box shell;,.o fia .conyentionalssternztubeof a a ship and; around; the: hips :propellen; shaft and against 1theinternal; annular shoulder ofi'said shellg:saidcassembly comprisingan, annulanair qti-ght texpansiblestube, nular finformed;;0n-:'the:;outen periphery jrof saidctube; means .-,;toghold. andhousetsaiditubeacqmprisingtairing assembly 1 formed of. two; mating;rhigsmdaptedz to:

fixedlyisecuted togethen'andio gfipping1enldsejesaidi 1 i V fi;lal;.fin;and to laterally-and freely' enclosetsaidftube; and conduitmeans extendingthroughsaid:shell-anclringr assembly andr-intotsaid rtubeadaptedri to introduce preset surized fluidinto saiditubezto expandthesame int'mpre'ss a ing ehgagementzwithr the iperiphery ofsaidishafrito pre vent the influx of sea water along said shaft when thepacking rings of said stufling box are being removed and replaced, saidtube being initially adapted to be wrapped around the shaft and saidmating rings being each formed of a plurality of complemental arcuatesections, with the sections of one ring being staggered with respect tothe sections of the other ring, whereby said tube and ring assembly maybe positioned around the shaft while said shaft remains in place.

2. A safety ring assembly adapted to be fixedly disposed within thestuffing box shell of a conventional stern tube of a ship immediatelyadjacent an annular shoulder formed in said shell and in spacedconcentric relation to the ships propeller shaft, said assemblycomprising an annular air tight expansible tube, an annular fin formedon the outer periphery of said tube, means to hold and house said tubecomprising a ring assembly formed of major and minor mating ringsadapted to be fixedly secured together to grippingly enclose saidannular fin, and conduit means extending through said shell and ringassembly and into said tube adapted to introduce pressurized fluid intosaid tube to expand the same into pressing engagement with the peripheryof said shaft to said minor n'ng being disposed adjacent said fin andthe outer periphery of said tube whereby said tube when expanded mayalso press against said annular shoulder and effect a water seal betweensaid ring assembly and said stufling box shell.

References Cited in the file of this patent UNITED STATES PATENTS632,442 Byle Sept. 5, 1899 2,038,140 Stone Apr. 21, 1934 2,174,075Borchardt Sept. 26, 1939 2,257,119 Johannesen Sept. 30, 1948 2,438,153Dick Mar. 23, 1948 2,648,554 Gilbert Aug. 11, 1953 FOREIGN PATENTS647,650 Great Britain Oct. 6, 1948 679,919 Great Britain May 18, 1950

